Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:104810
To: internals@lists.php.net
References: <a70baca7-f0af-49de-9cf9-5421e42e0a0c@www.fastmail.com>
 <CAFMT4No7F-vBgSToHMVqu4oYz52oLXfAp7QbUzGQLmMiQYYY9g@mail.gmail.com>
Message-ID: <fc5bd556-ca15-e850-7b3b-be04d8cdfe45@gmail.com>
Date: Tue, 19 Mar 2019 22:31:51 +0000
User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101
 Thunderbird/60.5.3
MIME-Version: 1.0
In-Reply-To: <CAFMT4No7F-vBgSToHMVqu4oYz52oLXfAp7QbUzGQLmMiQYYY9g@mail.gmail.com>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Transfer-Encoding: 7bit
Content-Language: en-GB
Subject: Re: [PHP-DEV] RFC Draft: Comprehensions
From: rowan.collins@gmail.com (Rowan Collins)

On 19/03/2019 20:24, Levi Morrison wrote:
> Today in the Dart world, Bob Nystrom published an article called
> [Making Dart a Better Language for UI][1]. I think it's an incredibly
> relevant article, since it is essentially about comprehensions, why
> they are a thing, as well as some of the design choices they made.
>
> I think everyone in this thread ought to spend the 10-15 minutes reading it.
>
>    [1]: https://medium.com/dartlang/making-dart-a-better-language-for-ui-f1ccaf9f546c
>

Hi Levi,

That is indeed a very interesting article, thanks for sharing.

The idea of foreach and if just being available whenever you're 
specifying an array is a really interesting version of this construct.


The mention of the spread operator has actually given me a different 
idea, related to iterator_to_array. What if the "..." operator could 
spread any iterable, not just arrays as currently proposed in an RFC [1]?

$iterator = new SomethingIterator;
$array = [ ...$iterator ];

$array2 = [ ...someGenerator() ];


That plus the current comprehension proposal would give us this:

$array = [ ...[ foreach $list as $x if $x % 2 yield $x*2] ];

Which could fairly naturally be special cased to this:

$array = [ ... foreach $list as $x if $x % 2 yield $x*2 ];


This would give us concise syntax for both iterator and array forms, in 
a way that fits the rest of the language better than () vs [].


[1]: https://wiki.php.net/rfc/spread_operator_for_array

-- 
Rowan Collins
[IMSoP]